Background: Tracking various biomarkers in serum, gingival crevicular fluid (GCF), and saliva has been introduced as a diagnostic tool for periodontal disease detection.Objectives: The aim of this study was to compare salivary lactate dehydrogenase (LDH) levels in subjects with periodontal disease and levels in subjects without periodontal disease.Materials and Methods: In this case-control study, 170 patients at Hamadan faculty of Dentistry, including patients with periodontal disease and patients with normal periodontium, were selected and divided into test and control groups. Unstimulated saliva was collected in the same situation from the test and control groups. Each saliva sample was analyzed to measure salivary LDH level on the day of collection, by using commercially available kits according to the manufacturers’ instructions. A statistical T-test was employed to evaluate significant differences among groups.Results: The mean LDH levels in the test and control groups were 1071.67731.004 and 550.91217.215, respectively. As the level of statistical significance was set at P<0.05, data analysis showed a significant difference between the LDH enzymatic level in the test and control groups (P=0.000). Comparison of the LDH enzymatic level in subjects with different genders in the test and control groups showed no significant differences (P=0.340).Conclusions: Salivary LDH levels can be used as marker of periodontal disease for screening periodontitis in large populations.

Introduction: Periodontitis is a chronic multi-factorial infectious disease characterized by irreversible destruction of collagen fibers and other matrix constituents of the gingival tissues and periodontal ligament, and resorption of alveolar bone around the teeth with periodontal pocket formation. Host response to periodontal disease includes production of different enzymes that are released by stromal, epithelial or inflammatory cells associated with cell injury and cell death, including aspartate aminotransferase and lactate dehydrogenase. The aim of this study was to compare aspartate aminotransferase and lactate dehydrogenase salivary levels in patients with generalized aggressive periodontitis and chronic mild-to-moderate periodontitis and healthy subjects with normal periodontium.Materials and Methods: In this experimental study, unstimulated saliva of 25 patients with mild-tomoderate periodontitis, 15 patients with aggressive periodontitis, and 25 subjects with healthy gingiva were collected. The mean aspartate aminotransferase and lactate dehydrogenase salivary levels were measured by RA-ST autoanalyzer system. Data were analyzed by ANOVA and Tukey test.Results: The mean levels and standard deviations of lactate dehydrogenase salivary enzyme in generalized aggressive periodontitis, chronic mild-to-moderate periodontitis and control groups were 1713±88.4, 1492±65.4, 1108±34.5, respectively, with significant differences between the groups (p value<0.05) The mean levels and standard deviations of aspartate aminotransferase salivary enzyme in generalized aggressive periodontitis, chronic mild-to-moderate periodontitis and control groups were 55.46±5.6, 47.04±3.3 and 32.04±2.3, respectively, with significant differences (p value<0.05).Conclusion: Mean levels of aspartate aminotransferase and lactate dehydrogenase salivary enzymes in periodontal patients were higher than those in healthy subjects and these enzymes can be good markers for determining amount of destruction of periodontal tissues.

Background and Aim: Smoking is a hazardous habit with numerous adverse effects on oral health. It plays an important role in development of cancerous and precancerous lesions and periodontal disease. Saliva has an antioxidant system and several enzymes. This study aimed to assess the salivary levels of uric acid (UA), lactate dehydrogenase (LDH), and amylase in smokers versus non-smokers. Materials and Methods: This descriptive, cross-sectional study was conducted on 60 individuals (30 smokers and 30 non-smokers) at the Dental School of Islamic Azad University. The participants were requested to refrain from smoking, eating and drinking prior to saliva sampling. A minimum of 1 cc of unstimulated saliva was collected from each participant by the spitting method. The level of salivary LDH was measured by the DGKC method, the level of UA was measured by the uricase assay, and the level of amylase was quantified by the kinetic photometric method. Data were analyzed by t-test, Chi-square test, Fisher’, s exact test, and Mann-Whitney test (P<0. 05). Results: The salivary level of UA was 1. 35±, 1. 2 mg/dL and 1. 08±, 1. 05 mg/dL in smokers and nonsmokers, respectively with no significant difference (P=0. 08). The salivary levels of amylase and LDH were 44509±, 38062 U/L and 420±, 244 IU/L in smokers and 47299±, 29659 U/L and 538±, 350 IU/L in non-smokers, respectively, with no significant difference (P>0. 05). Conclusion: Despite the slightly higher level of salivary UA in smokers, the difference between smokers and non-smokers was not significant in any of the tested parameters.

Background: lactate dehydrogenase (LDH) is a tetrameric enzyme that catalyzes the interconversion of pyruvate to L-lactate. The importance of this enzyme is because LDH isoenzymes are involved in cancer, heart, and liver diseases. Inhibition of this enzyme can help prevent and treat different diseases. Morin is a flavonoid found in the Moraceae family and scopoletin is a coumarin found in Scopolia genus. Objectives: The aim of this study was to determine the effect of morin and scopoletin as two natural products on the activity and structure of lactate dehydrogenase enzyme. Methods: Morin and scopoletin were examined for inhibition of the activity of LDH in 100mMsodium phosphate buffer pH 7. 5, at room temperature using UV-V spectrophotometry. Fluorescence spectroscopy was used to characterize protein structural changes in the presence of morin and scopoletin. Results: Km and Vmax of LDH for pyruvate were 11. 69 mM and 1. 258 mM/min, respectively. The kinetic results showed that morin and scopoletin are LDH inhibitors. The Ki values of morin and scopoletin were determined as 1. 78  M and 0. 8  M, respectively, using a secondary plot. Fluorescence intensity quenching and red shift of themaximumwavelength of emission in a concentrationdependent manner showed that morin and scopoletin bind to LDH and affect its structure. Conclusions: The results suggest that morin and scopoletin bind to LDH, influence its conformation and inhibit its activity. Scopoletin showed more effective inhibition of LDH activity and it can be a promising candidate in the field of tumor metabolism inhibitors.

The aim of this study was to assess the effects of intermittent training on lactate level and lactate dehydrogenase enzyme activity in Wistar rats. 20 male Wistar rats (mean age 3 months and weight 224± 14 g) were selected and randomly divided into the training (11=10) and control (11=10) groups. The training protocol consisted of running on a treadmill for 4 minutes and then 2 minutes of active rest in J 0 training phases for the experimental group. All rats were anesthetized with a mixture of ketarnine and xylazine 48 hours after the last training session after an overnight fasting. To measure lactate and LDH enzyme activity, blood samples were obtained from their cardiac puncture. Data were analyzed by mean and standard deviation (M±SD) and independent t test. The results showed no significant differences in blood lactate level between the two groups, but there was a significant difference in LOH enzyme activity between the two groups (P<0.05). These results indicate that intermittent training caused the clearance of lactate. Enhance of lactate replenished muscle glycogen and prevented H+ concentration which was produced along with lactate.